The present invention relates to bumper impact system designs for motor vehicles that are required to meet all or part of the Federal Motor Vehicle Safety Standards and Insurance Institute for Highway Safety guidelines for bumpers. These designs are driven by the need to absorb as much impact energy as possible in the shortest distance possible (stroke) for purposes of keeping the package size of the bumper system reasonable. In addition, it has been found desirable to absorb as much energy as possible with the least system mass (optimized “specific energy”) in order to minimize bumper impact system mass, always a mandate with today's strict emission standards.
Typical bumper performance is based on its ability to protect a vehicle. A typical bumper design usually consists of a profile or closed section that reaches across a vehicle transverse to its usual direction of travel. The bumper may be disposed at either the front or rear of a vehicle. The following description refers to a front bumper, but should be considered applicable to a rear bumper as well.
A conventional bumper beam/fascia assembly consists of a specific vehicle-designed fascia (plastic), filler (foam), then a bumper beam (steel or equivalent) that is to be mounted horizontally at the end of the vehicle, to the front ends of the side rails of the vehicle. The mounting of the bumper beam at the side rails may be accomplished by any chosen method.
With the bumper beam mounted onto the vehicle, its main task is to help meet, distribute, and dissipate the energy that is absorbed during a collision between the vehicle and another object. The bumper beam should mainly address and mitigate those forces that act on the vehicle during a collision directly from the front or rear or obliquely from the front or rear. Improved performance is attained by moving the beam (armature) edge as close as possible to the vehicle exterior surface. Foam or other material is used to fill gaps between the bumper beam and the fascia that typically exists, which adds extra cost and limits performance. Therefore, further improvements on the bumper beam design are desirable.